1. Technical Field
This invention relates to the field of data processing systems. More particularly, this invention relates to the user interface of data processing systems.
In the past the use of data processing systems has typically been large centralised systems operated and controlled by a small number of expert users. However, the use of data processing systems has recently undergone dramatic changes in that small data processing systems (e.g. personal computers) are being used as an everyday working tool by users having jobs ranging from the factory floor to senior management.
These new users are not experts in data processing systems and their priority is that the data processing systems should give them the maximum help with their jobs rather than a desire to become experts in data processing systems. Thus, in order to meet the priorities of these new users, the way in which the user interacts with the data processing system should be made easy to learn and simple to work with, i.e. the user interface should be rationalised.
Great strides have been made in improving the user interfaces of data processing systems. One successful approach has been the development of so called `window driven systems` such as the Presentation Manager feature of the OS/2 systems of International Business Machines Corporation (Presentation Manager and OS/2 are a trademarks of International Business Machines Corporation)
Such systems provide a number of display areas (windows) whose size, shape and position within the display may be manipulated by the user. Each of these windows presents a different portion of the user interface, i.e. one window may display a menu of program options within a word processing program whilst another displays the text being manipulated by that word processing program.
These windows driven user interfaces have been found to be particularly effective for multitasking data processing systems in which more than one application program is in use at any time, e.g. a word processing program, an electronic mail program, a database program and a graphics program may all be in use at one time. Each of these application programs will have one or more windows by means of which the user interacts with that application. It will be appreciated that the different application programs/tasks are distinct self contained pieces of software such as the application programs listed above. The multitasking system interleaves the execution of the program. Such a mode of operation is quite distinct from the sequential execution of different routines within the same program.
It is a feature of advanced multitasking data processing systems that the tasks executed are becoming more interdependent, i.e. one task may start or call upon another task to carry out some function required by that first task. An example of such interdependence would be one task requiring a particular piece of information to be retrieved from a database by a database retrieval task. The calling task would start the database retrieval task and pass to it details concerning the data required. In prior art systems the calling task would have one set of windows and the called task would have a separated set of windows. In the case of a called database retrieval task its window may provide visual feedback to the user concerning the progress of the search.
Whilst it is desirable to provide this visual feedback, consequential problems do arise. To the non-expert user, the separate window of the called task seems to appear out of nowhere and be unconnected to the window of the calling task. Furthermore, the movement, shrinking or closing of the window of the calling task has no effect on the window of the called task. There is a lack of visual connection between the window(s) of the calling and called tasks. The present invention both recognising and solves this problem.